A Rare Bone to Pick: Solitary Clavicle Metastasis from Cervical Carcinoma on ¹⁸F-FDG PET/CT

INTRODUCTION

Cervical cancer is one of the most common malignancies in the female genital tract system. It is the second leading cause of cancer mortality in women aged 20–39 years.^[1]Regardless of the several strategies for prevention, diagnosis, and treatment that are applied to the disease, the prognosis of cervical cancer patients remains poor, especially in metastatic patients. Previous studies have shown that the median survival time of metastatic cervical cancer is only 8–13 months, and the 5-year survival rate is 16.5%.^[2,3] Due to the poor prognosis, metastatic cervical cancer has become one of the main challenges in the world. The common sites of metastasis included the lung, bone, and liver. In single-site metastasis, lung metastasis was the most common, accounting for 37.9% of all patients, followed by bone metastasis (16.7%) and liver metastasis (12.5%).^[4]

Bone metastases typically involving the spine or pelvic bones and are often seen in advanced or recurrent disease. However, solitary bone metastasis to the clavicle is extremely rare. Bone metastases are most commonly identified during disease recurrence, and their isolated presence at initial diagnosis is relatively rare. When detected during initial staging. It usually signifies systemic dissemination even before locoregional treatment is initiated. Such early detection profoundly impacts clinical decision-making, as it alters the therapeutic goal from curative to palliative intent in locally advanced cases.

We present a case of carcinoma cervix with solitary clavicular metastasis detected during initial staging using ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) – an unusual site and timing of metastasis that significantly altered the treatment approach.

CASE REPORT

A 56-year-old postmenopausal woman presented with vaginal bleeding and white discharge per vaginum. Clinical examination revealed blood-stained discharge per vaginum. Cervical cytology was positive for malignant cells, and biopsy confirmed moderately differentiated squamous cell carcinoma. Magnetic resonance imaging (MRI) pelvis showed a lobulated mass involving the cervix, lower uterine segment, and vaginal fornices with right medial parametrial invasion and a metastatic enlarged right external iliac node, consistent with the International Federation of Gynecology and Obstetrics (FIGO) stage IIB, (T2B N1 Mx).

Whole-body ¹⁸F-FDG PET/CT revealed an FDG-avid cervical mass, right external iliac node, and an unexpected FDG-avid lytic lesion in the medial end of the left clavicle [Fig 1].

Close

Fig 1: (A) Maximum intensity projection image of the whole body showing increased fluorodeoxyglucose (FDG) uptake in the pelvic region and left chest wall (arrow); (B and C) Fused axial positron emission tomography/computed tomography (PET/CT) image of the pelvic cavity showing intense FDG uptake in the cervical mass (4.0 cm × 4.6 cm × 5.0 cm, SUVmax 10.23) (blue thin arrow); (D and E) Low grade FDG uptake in the right external iliac node (14 mm × 9 mm SUVmax 3.91) (white thin arrow); (F and G) Axial CT and fused PET/CT image showing increased FDG uptake in the medial end of the left clavicle with soft tissue component (3.0 cm × 3.8 cm, SUVmax 11.70) (vertical bold arrow) SUVmax: Maximum standardised uptake value

Export to PPT

CT-guided biopsy [Fig 2] of the clavicular lesion confirmed metastatic squamous cell carcinoma. The disease was upstaged to FIGO stage IVB, and treatment was modified to palliative chemotherapy with local radiotherapy to the clavicle.

Close

Fig 2: (A) H and E 100x : Photomicrograph shows poorly differentiated squamous cells arranged in sheets and nests with focal palisading (indicated by the green arrow); (B) H and E 400x : Keratin pearl formation is noted (indicated by the red arrow); (C) H and E 1000x : Tumour cells show intercellular bridges (indicated by the yellow arrow). H and E: Haematoxylin and eosin

Export to PPT

DISCUSSION

Cervical cancer remains a major global health burden, particularly in low- and middle-income countries, where access to human papillomavirus vaccination and routine screening is limited. It is the second most common malignancy in women of reproductive age in terms of both incidence and mortality, with the highest prevalence in countries with the lowest Human Development Index.^[5,6] The disease typically follows an orderly pattern of spread, with initial dissemination to pelvic and para-aortic lymph nodes, and distant metastases occurring only in advanced stages.^[7]

Bone metastases from cervical carcinoma are uncommon, reported in 0.8% to 23% of cases, and are generally seen in patients with advanced disease.^[8-10] In a retrospective study by Matsuyama et al., bone metastasis was identified in 4.0% of patients with stage I disease and rose progressively to 22.9% in stage IV.^[11] The most common site of bone metastasis was the lumbar spine (51.9%), followed by pelvis (29.6%), thoracic spine (27.8%), cervical spine (16.7%), and sacrum (14.8%).^[11,12] These sites are favoured due to their rich venous plexus and red marrow content.

In contrast, metastases to the appendicular skeleton, such as the femur, fibula, or patella, are rare.^[13-15] Solitary clavicular metastases from cervical carcinoma are exceptionally uncommon and, to our knowledge, this is the first reported case of clavicular involvement identified at the time of primary diagnosis. Previous case reports have described the occurrence of clavicular metastases only during follow-up, several months after completion of initial treatment.^[16]

The mechanism of skeletal metastasis in cervical cancer includes direct extension from pelvic tumours or lymph nodes, hematogenous spread via Batson’s paravertebral venous plexus, or systemic arterial dissemination.^[17] The isolated nature of clavicular involvement in our case suggests hematogenous seeding as the most plausible route.

Radiological evaluation is essential in identifying bone metastases. While plain radiographs and CT scans are helpful, MRI offers superior soft tissue contrast for marrow involvement, and FDG-PET/CT is highly sensitive for detecting both skeletal and visceral metastases.^[18] In our case, PET/CT not only localised the clavicular lesion but also guided the biopsy that confirmed metastatic disease.

Bone metastases are associated with a poor prognosis and significant morbidity, including pain, fractures, and reduced mobility. Management is typically palliative and includes systemic chemotherapy, radiotherapy, and bone-modifying agents such as bisphosphonates or denosumab.^[19] In selected cases, local surgical intervention may be warranted for pain relief or structural stabilisation. In our case patient received chemoradiation for local disease and definitive radiotherapy to the clavicle.

This case highlights a rare and unusual presentation of cervical cancer, emphasising the need for a high index of suspicion for metastatic disease in patients presenting with unexplained bony lesions. It also reinforces the value of PET/CT imaging in evaluating atypical sites of disease and broadens our understanding of the metastatic potential of cervical carcinoma.

CONCLUSION

This case highlights an exceptionally rare presentation of cervical carcinoma with solitary clavicular metastasis detected at initial staging. Such atypical metastatic patterns challenge the conventional understanding of disease spread and underscore the importance of comprehensive whole-body imaging. The use of ¹⁸F-FDG PET/CT proved invaluable in identifying an unexpected site of metastasis, thereby significantly altering the staging and therapeutic approach from curative to palliative intent.